Multi-component fibers having enhanced reversible thermal properties and methods of manufacturing thereof

ABSTRACT

The invention relates to a multi-component fiber having enhanced reversible thermal properties and methods of manufacturing thereof. The multi-component fiber comprises a fiber body formed from a plurality of elongated members, at least one of the elongated members comprising a temperature regulating material dispersed therein. The temperature regulating material comprises a phase change material. The multi-component fiber may be formed via a melt spinning process or a solution spinning process and may be used or incorporated in various products where a thermal regulating property is desired. For example, the multi-component fiber may be used in textiles, apparel, footwear, medical products, containers and packagings, buildings, appliances, and other products.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of patents applications ofHaggard, entitled “Temperature Adaptable Textile Fibers and Method ofPreparing Same”, U.S. Ser. No. 09/691,164, filed on Oct. 19, 2000, andMagill et al., entitled “Multi-component Fibers Having EnhancedReversible Thermal Properties”, U.S. Ser. No. 09/960,591, filed on Sep.21, 2001, which claims the benefit of U.S. Provisional Application Ser.No. 60/234,410, filed on Sep. 21, 2000, the disclosures of which areincorporated herein by reference in their entirety.

The present invention is related to the inventions disclosed in thecopending patent applications of Hartmann, entitled “Stable Phase ChangeMaterials For Use In Temperature Regulating Synthetic Fibers, FabricsAnd Textiles”, U.S. Ser. No. 09/960,901, filed on Sep. 21, 2001, andHartmann et al., entitled “Melt Spinnable Concentrate Pellets HavingEnhanced Reversible Thermal Properties”, U.S. Ser. No. 09/777,512, filedFeb. 6, 2001, the disclosures of which are incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates to synthetic fibers having enhancedreversible thermal properties. More particularly, the present inventionrelates to multi-component fibers comprising phase change materials andto the formation of such fibers via a melt spinning process or asolution spinning process.

BACKGROUND OF THE INVENTION

Many fabrics are made from synthetic fibers. Conventionally, twoprocesses are used to manufacture synthetic fibers: a solution spinningprocess and a melt spinning process. The solution spinning process isgenerally used to form acrylic fibers, while the melt spinning processis generally used to form nylon fibers, polyester fibers, polypropylenefibers, and other similar type fibers. As is well known, a nylon fibercomprises a long-chain synthetic polyamide polymer characterized by thepresence of an amide group —CONH—, a polyester fiber comprises along-chain synthetic polymer having at least 85 percent by weight of anester of a substituted aromatic carboxylic acid unit, and apolypropylene fiber comprises a long-chain synthetic crystalline polymerhaving at least 85 percent by weight of an olefin unit and typicallyhaving a number average molecular weight of about 40,000 or more.

The melt spinning process is of particular interest since a largeportion of the synthetic fibers that are used in the textile industryare manufactured by this technique. The melt spinning process generallyinvolves passing a molten polymeric material through a device that isknown as a spinneret to thereby form a plurality of individual syntheticfibers. Once formed, the synthetic fibers may be collected into a strandor cut into staple fibers. Synthetic fibers can be used to make knitted,woven, or non-woven fabrics, or alternatively, synthetic fibers can bespun into a yarn to be used thereafter in a weaving or a knittingprocess to form a synthetic fabric.

Phase change materials have been incorporated into mono-componentacrylic fibers to provide enhanced reversible thermal properties to thefibers themselves as well as to fabrics made therefrom. This is readilyaccomplished, in part due to the high levels of volatile materials(e.g., solvents) typically associated with the solution spinning processof forming acrylic fibers. However, it is more problematic toincorporate phase change materials into melt spun synthetic fibers,since high levels of volatile materials typically are not present ordesired in the melt spinning process. Previous attempts to incorporatephase change materials into melt spun synthetic fibers typicallyinvolved mixing microcapsules containing a phase change material with astandard fiber-grade thermoplastic polymer to form a blend andsubsequently melt spinning this blend to form mono-component syntheticfibers. Such attempts generally led to inadequate dispersion of themicrocapsules within the fibers, poor fiber properties, and poorprocessability unless low concentrations of the microcapsules were used.However, with low concentrations of the microcapsules, the desiredenhanced reversible thermal properties normally associated with use ofphase change materials are difficult to realize.

It is against this background that a need arose to developmulti-component fibers comprising phase change materials.

SUMMARY OF THE INVENTION

In one innovative aspect, the present invention relates to amulti-component fiber having enhanced reversible thermal properties. Inone exemplary embodiment, the multi-component fiber may comprise a fiberbody formed from a plurality of elongated members, wherein at least oneof the elongated members comprises a temperature regulating materialdispersed therein.

In another exemplary embodiment, the multi-component fiber may comprisea first elongated member comprising a first polymeric material and atemperature regulating material dispersed within the first polymericmaterial. The multi-component fiber also may comprise a second elongatedmember comprising a second polymeric material, wherein the secondelongated member is joined with the first elongated member.

In still another exemplary embodiment, the multi-component fiber maycomprise a core member that comprises a temperature regulating material.The multi-component fiber may further comprise a sheath member thatsurrounds the core member.

In a second innovative aspect, the present invention relates to a fiberhaving enhanced reversible thermal properties. In one exemplaryembodiment, the fiber may comprise at least one inner member extendingthrough substantially the length of the fiber and comprising a blend ofa first polymeric material and a temperature regulating material. Anouter member may surround the inner member and form the exterior of thefiber, wherein the outer member comprises a second polymeric material.

In a third innovative aspect, the present invention relates to acore/sheath fiber. In one exemplary embodiment, the core/sheath fibermay comprise a core member positioned within and extending throughsubstantially the length of the fiber, wherein the core member comprisesa blend of a first polymeric material and a temperature regulatingmaterial. The core/sheath fiber may further comprise a sheath memberforming the exterior of the fiber and surrounding the core member,wherein the sheath member comprises a second polymeric material.

In a fourth innovative aspect, the present invention relates to anisland-in-sea fiber. In one exemplary embodiment, the island-in-seafiber may comprise a plurality of island members positioned within andextending through substantially the length of the fiber, wherein each ofthe island members is separated from one another and comprises a blendof an island polymeric material and a temperature regulating material.The island-in-sea fiber may further comprise a sea member forming theexterior of the fiber and surrounding each of the island members,wherein the sea member comprises a sea polymeric material.

In a fifth innovative aspect, the present invention relates to a methodof manufacturing and processing a fiber having enhanced reversiblethermal properties. In one exemplary embodiment, the method may comprisemixing a temperature regulating material with a first polymeric materialso as to form a blend and combining the blend with a second polymericmaterial in a spin pack of a fiber extrusion apparatus such that thesecond polymeric material surrounds the blend. The method may furthercomprise extruding the blend and the second polymeric material from aspinneret of the spin pack so as to form a fiber having an outer memberformed of the second polymeric material and surrounding an inner memberformed of the blend.

In a sixth innovative aspect, the present invention relates to a methodof manufacturing a fiber having enhanced reversible thermal properties.In one exemplary embodiment, the method may comprise forming a pluralityof separate blends, wherein each blend comprises a temperatureregulating material and a first polymeric material, and combining theplurality of separate blends with a second polymeric material in a spinpack of a fiber extrusion apparatus such that the second polymericmaterial surrounds the plurality of separate blends. The method mayfurther comprise extruding the plurality of separate blends and thesecond polymeric material from a spinneret of the spin pack so as toform a fiber having an outer member formed of the second polymericmaterial and surrounding a plurality of inner members formed of theplurality of separate blends.

In a seventh innovative aspect, the present invention relates to afabric. In one exemplary embodiment, the fabric may comprise a pluralityof fibers blended together, wherein at least one fiber exhibits enhancedreversible thermal properties. The fiber may comprise at least one innermember comprising a blend of a first polymeric material and atemperature regulating material, wherein the inner member extendsthrough substantially the length of the fiber. The fiber may furthercomprise an outer member forming the exterior of the fiber andsurrounding the inner member, wherein the outer member comprises asecond polymeric material.

In another exemplary embodiment, the fabric may comprise a plurality offibers blended together, wherein at least one fiber exhibits enhancedreversible thermal properties. The fiber may comprise a fiber bodyformed from a plurality of elongated members, wherein at least one ofthe elongated members comprises a temperature regulating materialdispersed therein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the invention,reference should be made to the following detailed description taken inconjunction with the accompanying drawings.

FIG. 1 illustrates enlarged cross sectional views of various exemplarymulti-component fibers according to some embodiments of the invention.

FIG. 2 illustrates a three-dimensional view of an exemplary core/sheathfiber according to an embodiment of the invention.

FIG. 3 illustrates a three-dimensional view of another exemplarycore/sheath fiber according to an embodiment of the invention.

FIG. 4 illustrates a three-dimensional view of an exemplaryisland-in-sea fiber according to an embodiment of the invention.

FIG. 5 illustrates an exemplary fiber extrusion apparatus for formingmulti-component fibers in accordance with an embodiment of theinvention.

FIG. 6 shows a number of properties and manufacturing parameters of sixcore/sheath fibers that were produced as discussed in Example 1.

DETAILED DESCRIPTION

The present invention relates to multi-component fibers comprising oneor more phase change materials and methods of manufacturing thereof.Multi-component fibers in accordance with various embodiments of theinvention have the ability to absorb or release thermal energy to reduceor eliminate heat flow. In addition, such multi-component fibers mayexhibit improved processability (e.g., during manufacturing of thefibers or of a product made therefrom), improved strength, improvedcontainment of a phase change material within the fibers, or higherloading levels of the phase change material. The multi-component fibersmay be used or incorporated in various products to provide a thermalregulating property while providing improved strength to the products.For example, multi-component fibers in accordance with embodiments ofthe invention may be used in textiles (e.g., fabrics), apparel (e.g.,outdoor clothing, drysuits, and protective suits), footwear (e.g.,socks, boots, and insoles), medical products (e.g., thermal blankets,therapeutic pads, incontinent pads, and hot/cold packs), containers andpackagings (e.g., beverage/food containers, food warmers, seat cushions,and circuit board laminates), buildings (e.g., insulation in walls orceilings, wallpaper, curtain linings, pipe wraps, carpets, and tiles),appliances (e.g., insulation in house appliances), and other products(e.g., automotive lining material, sleeping bags, and bedding).

In conjunction with the thermal regulating property provided,multi-component fibers in accordance with various embodiments of thepresent invention when incorporated, for example, in apparel or footwearmay provide a reduction in an individual's skin moisture, such as, dueto perspiration. For instance, the multi-component fibers may lower thetemperature or the relative humidity of the skin, thereby providing alower degree of skin moisture and a higher level of comfort. The use ofspecific materials and specific apparel or footwear design features mayfurther enhance this moisture reduction result.

A multi-component fiber according to some embodiments of the inventionmay comprise a plurality of elongated members. According to someembodiments of the invention, the multi-component fiber may comprise afiber body formed from the plurality of elongated members. The fiberbody typically will be elongated and may have a length that is severaltimes (e.g., 100 times or more) greater than its diameter. The fiberbody may have a variety of regular or irregular cross sectional shapessuch as, by way of example and not by limitation, circular, multi-lobal,octagonal, oval, pentagonal, rectangular, square-shaped, trapezoidal,triangular, wedge-shaped, and so forth. According to some embodiments ofthe invention, two or more of the elongated members (e.g., two adjacentelongated members) may be joined, combined, united, or bonded to form aunitary fiber body.

According to some embodiments of the invention, at least one of theelongated members will comprise a temperature regulating material.Typically, the temperature regulating material will comprise one or morephase change materials to provide the multi-component fiber withenhanced reversible thermal properties. In some embodiments of theinvention, the elongated members may comprise the same or differentpolymeric materials, and at least one of the elongated members may havethe temperature regulating material dispersed therein. Typically, thetemperature regulating material will be uniformly dispersed within atleast one of the elongated members. However, depending upon theparticular characteristics desired from the multi-component fiber, thedispersion of the temperature regulating material may be varied withinone or more of the elongated members. According to some embodiments ofthe invention, two or more elongated members may comprise the same ordifferent temperature regulating materials.

Depending upon the particular application of the multi-component fiber,the elongated members may be arranged in one of a variety ofconfigurations. For instance, the elongated members may be arranged inan island-in-sea configuration or a core-sheath configuration. Theelongated members may be arranged in other configurations such as, byway of example and not by limitation, a matrix or checkerboardconfiguration, a segmented-pie configuration, a side-by-sideconfiguration, a striped configuration, and so forth. According to someembodiments of the invention, the elongated members may be arranged in abundle form wherein the elongated members are generally parallel withrespect to one another. According to other embodiments of the invention,one or more elongated members may extend through at least a portion ofthe length of the fiber body, and, if desired, the elongated members maybe longitudinally coextensive. For example, according to someembodiments of the invention, at least one inner member may extendthrough substantially the length of the multi-component fiber andcomprise a temperature regulating material. The extent to which theinner member extends through the length of the multi-component fiber maydepend on, for example, desired thermal regulating properties for themulti-component fiber. In addition, other factors (e.g., desiredmechanical properties or method of forming the multi-component fiber)may play a role in determining this extent. Thus, in one embodiment, theinner member may extend through from about a half up to the entirelength of the multi-component fiber to provide desired thermalregulating properties. An outer member may surround the inner member andform the exterior of the multi-component fiber.

According to some embodiments of the invention, the multi-componentfiber may be between about 0.1 to about 1000 denier or between about 0.1to about 100 denier. Typically, the multi-component fiber according toan embodiment of the invention may be between about 0.5 to about 10denier. As one of ordinary skill in the art will understand, a denier istypically understood to be a measure of weight per unit length of afiber (i.e., grams per 9000 meters).

If desired, the multi-component fiber according to some embodiments ofthe invention may be further processed to form one or more smallerdenier fibers. For instance, the elongated members comprising themulti-component fiber may be split apart to form two or more smallerdenier fibers, wherein each smaller denier fiber may comprise one ormore of the elongated members. Alternatively or in conjunction, one ormore elongated members (or a portion or portions thereof) comprising themulti-component fiber may be dissolved or melted away to yield one ormore smaller denier fibers. Typically, at least one resulting smallerdenier fiber will comprise a temperature regulating material to providedesired thermal regulating properties.

Depending upon the method of manufacturing the multi-component fiber,desirability of further processing, or particular application of themulti-component fiber, the multi-component fiber may further compriseone or more additives, such as, by way of example and not by limitation,water, surfactants, dispersants, anti-foam agents (e.g., siliconecontaining compounds and fluorine containing compounds), antioxidants(e.g., hindered phenols and phosphites), thermal stabilizers (e.g.,phosphites, organophosphorous compounds, metal salts of organiccarboxylic acids, and phenolic compounds), light or UV stabilizers(e.g., hydroxy benzoates, hindered hydroxy benzoates, and hinderedamines), microwave absorbing additives (e.g., multifunctional primaryalcohols, glycerine, and carbon), reinforcing fibers (e.g., carbonfibers, aramid fibers, and glass fibers), conductive fibers or particles(e.g., graphite or activated carbon fibers or particles), lubricants,process aids (e.g., metal salts of fatty acids, fatty acid esters, fattyacid ethers, fatty acid amides, sulfonamides, polysiloxanes,organophosphorous compounds, silicon containing compounds, fluorinecontaining compounds, and phenolic polyethers), fire retardants (e.g.,halogenated compounds, phosphorous compounds, organophosphates,organobromides, alumina trihydrate, melamine derivatives, magnesiumhydroxide, antimony compounds, antimony oxide, and boron compounds),anti-blocking additives (e.g., silica, talc, zeolites, metal carbonates,and organic polymers), anti-fogging additives (e.g., non-ionicsurfactants, glycerol esters, polyglycerol esters, sorbitan esters andtheir ethoxylates, nonyl phenyl ethoxylates, and alcohol ethyoxylates),anti-static additives (e.g., non-ionics such as fatty acid esters,ethoxylated alkylamines, diethanolamides, and ethoxylated alcohol;anionics such as alkylsulfonates and alkylphosphates; cationics such asmetal salts of chlorides, methosulfates or nitrates, and quaternaryammonium compounds; and amphoterics such as alkylbetaines),anti-microbials (e.g., arsenic compounds, sulfur, copper compounds,isothiazolins phthalamides, carbamates, silver base inorganic agents,silver zinc zeolites, silver copper zeolites, silver zeolites, metaloxides, and silicates), crosslinkers or controlled degradation agents(e.g., peroxides, azo compounds, and silanes), colorants, pigments,dyes, fluorescent whitening agents or optical brighteners (e.g.,bis-benzoxazoles, phenylcoumarins, and bis-(styryl)biphenyls), fillers(e.g., natural minerals and metals such as oxides, hydroxides,carbonates, sulfates, and silicates; talc; clay; wollastonite; graphite;carbon black; carbon fibers; glass fibers and beads; ceramic fibers andbeads; metal fibers and beads; flours; and fibers of natural orsynthetic origin such as fibers of wood, starch, or cellulose flours),coupling agents (e.g., silanes, titanates, zirconates, fatty acid salts,anhydrides, epoxies, and unsaturated polymeric acids), reinforcementagents, crystallization or nucleation agents (e.g., any material whichincreases or improves the crystallinity in a polymer, such as to improverate/kinetics of crystal growth, number of crystals grown, or type ofcrystals grown), and so forth. The one or more additives may bedispersed within one or more of the elongated members comprising themulti-component fiber.

According to some embodiments of the invention, certain treatments orcoatings may be applied to the multi-component fiber to impartadditional properties such as, by way of example and not by limitation,stain resistance, water repellency, softer feel, and moisture managementproperties. Exemplary treatments and coatings include Epic by NextecApplications Inc., Intera by Intera Technologies, Inc., Zonyl FabricProtectors by DuPont Inc., Scotchgard by 3M Co., and so forth.

With reference to FIG. 1, enlarged cross sectional views of variousexemplary multi-component fibers 12, 13, 14, 21, 22, 23, 24, 26, 27, 28,29, and 34 according to some embodiments of the invention areillustrated. More particularly, FIG. 1 illustrates a variety ofexemplary configurations of arranging elongated members comprising themulti-component fibers, according to some embodiments of the invention.

As shown in FIG. 1, each multi-component fiber (e.g., 21) comprises aplurality of distinct cross sectional regions corresponding to aplurality of elongated members (e.g., 39 and 40) that form themulti-component fiber. According to the presently illustratedembodiments, the elongated members include a first elongated member (ora first plurality of elongated members) (shown shaded in FIG. 1) and asecond elongated member (or a second plurality of elongated members)(shown unshaded in FIG. 1). Here, the first elongated member (or thefirst plurality of elongated members) preferably may be formed from apolymeric material that has a temperature regulating material dispersedtherein. The second elongated member (or the second plurality ofelongated members) may be formed from the same polymeric material oranother polymeric material having somewhat different properties. Itshould be recognized that the number, shapes, and sizes of the elongatedmembers shown in FIG. 1 are illustrated by way of example and not bylimitation, and various other embodiments are within the scope of theinvention.

While FIG. 1 illustrates multi-component fibers with circular ortri-lobal cross sectional shapes, multi-component fibers with a varietyof other regular or irregular cross sectional shapes are encompassed bythe invention, such as, by way of example and not by limitation,multi-lobal, octagonal, oval, pentagonal, rectangular, square-shaped,trapezoidal, triangular, wedge-shaped, and so forth. It should berecognized that, in general, a first plurality of elongated members maybe formed from the same or different polymeric materials, and a secondplurality of elongated members may be formed from the same or differentpolymeric materials. Moreover, a temperature regulating material may bedispersed within a second elongated member (or a second plurality ofelongated members), according to some embodiments of the invention. Itshould be further recognized that two or more different temperatureregulating materials may be dispersed within the same or differentelongated members. For instance, a first temperature regulating materialmay be dispersed within a first elongated member, and a secondtemperature regulating material having somewhat different properties maybe dispersed within a second elongated member (e.g., two different phasechange materials).

According to some embodiments of the invention, one or more elongatedmembers may be formed from a temperature regulating material that neednot be dispersed within a polymeric material. For instance, thetemperature regulating material may comprise a polymer (or mixture ofpolymers) that provides enhanced reversible thermal properties and thatmay be used to form a first elongated member (or a first plurality ofelongated members). For such embodiments of the invention, it may bedesirable, but not required, that a second elongated member (or a secondplurality of elongated members) adequately surrounds the first elongatedmember (or the first plurality of elongated members) to reduce orprevent loss or leakage of the temperature regulating material. Inaddition, it should be recognized that, in general, two or moreelongated members may be formed from the same or different temperatureregulating materials.

With reference to FIG. 1, left-hand column 10 illustrates threeexemplary multi-component fibers 12, 13, and 14. Multi-component fiber12 comprises a plurality of elongated members arranged in asegmented-pie configuration. In the present embodiment, a firstplurality of elongated members 15, 15′, 15″, 15′″, and 15″″ and a secondplurality of elongated members 16, 16′, 16″, 16′″, and 16″″ are arrangedin an alternating fashion and have cross sectional areas that arewedge-shaped. In general, the elongated members may have the same ordifferent cross sectional shapes or sizes. Moreover, whilemulti-component fiber 12 is shown comprising ten elongated members, itshould be recognized that, in general, two or more elongated members maybe arranged in a segmented-pie configuration, and at least one of theelongated members typically will comprise a temperature regulatingmaterial.

Multi-component fiber 13 comprises a plurality of elongated membersarranged in an island-in-sea configuration. In the present embodiment, afirst plurality of elongated members 35, 35′ 35″, 35′″, etc. extendsthrough substantially the length of the multi-component fiber 13 and areseparated from each other. The first plurality of elongated members 35,35′ 35″, 35′″, etc. is shown positioned within and completely surroundedby a second elongated member 36, thereby forming “islands” within the“sea” of the second elongated member 36. The arrangement of these“islands” within the “sea” may serve to provide a more uniformdistribution of a temperature regulating material within multi-componentfiber 13. In the present embodiment, each of the first plurality ofelongated members 35, 35′ 35″, 35′″, etc. has a cross sectional shapethat is trapezoidal. It should be recognized, however, that a variety ofother regular or irregular cross sectional shapes are encompassed by theinvention, such as, by way of example and not by limitation, circular,multi-lobal, octagonal, oval, pentagonal, rectangular, square-shaped,triangular, wedge-shaped, and so forth. In general, the first pluralityof elongated members 35, 35′, 35″, 35′″, etc. may have the same ordifferent cross sectional shapes or sizes. Moreover, whilemulti-component fiber 13 is shown with seventeen elongated members 35,35′, 35″, 35′″, etc. positioned within and surrounded by the secondelongated member 36, it should be recognized that, in general, one ormore elongated members may be positioned within and surrounded by thesecond elongated member 36.

Multi-component fiber 14 comprises a plurality of elongated membersarranged in a striped configuration. In the present embodiment, a firstplurality of elongated members 37, 37′, 37″, 37′″, and 37′″ and a secondplurality of elongated members 38, 38′, 38″, and 38′″ are arranged in analternating fashion and are shaped as longitudinal slices of themulti-component fiber 14. In general, the elongated members may have thesame or different cross sectional shapes or sizes (e.g., widthsassociated with the longitudinal slices). If desired, multi-componentfiber 14 may be a self-crimping or self-texturing fiber, wherein thefiber's crimping or texturing imparts loft, bulk, insulation, stretch,or other like properties to the fiber. While multi-component fiber 14 isshown comprising nine elongated members, it should be recognized that,in general, two or more elongated members may be arranged in a stripedconfiguration, and at least one of the elongated members typically willcomprise a temperature regulating material.

In the case of multi-component fibers 12 and 14, a first elongatedmember (e.g., 15) is shown partially surrounded by an adjacent secondelongated member or members (e.g., 16 and 16″″), whereas, in the case ofmulti-component fiber 13, a first elongated member (e.g., 35) is showncompletely surrounded by a unitary second elongated member 36. When afirst elongated member (e.g., 15) is not completely surrounded, it maybe desirable, but not required, that a containment structure (e.g.,microcapsules) be used to contain a phase change material dispersedwithin the first elongated member. If desired, multi-component fibers12, 13, and 14 may be further processed to form one or more smallerdenier fibers. Thus, for example, the elongated members comprisingmulti-component fiber 12 may be split apart, or one or more of theelongated members (or a portion or portions thereof) may be dissolved ormelted away. A resulting smaller denier fiber may, for example, comprisethe elongated members 15 and 16 that may be joined to one another.

Middle column 20 of FIG. 1 illustrates four exemplary core/sheath fibers21, 22, 23, and 24. In particular, core/sheath fibers 21, 22, 23, and 24each comprises a plurality of elongated members arranged in acore-sheath configuration.

Core/sheath fiber 21 comprises a first elongated member 39 positionedwithin and surrounded by a second elongated member 40. Moreparticularly, the first elongated member 39 is formed as a core memberthat comprises a temperature regulating material. This core member isshown concentrically positioned within and completely surrounded by thesecond elongated member 40 that is formed as a sheath member. Here,core/sheath fiber 21 comprises 25 percent by weight of the core memberand 75 percent by weight of the sheath member.

Core/sheath fiber 22 comprises a first elongated member 41 positionedwithin and surrounded by a second elongated member 42. As with thepreviously discussed embodiment, the first elongated member 41 is formedas a core member that comprises a temperature regulating material and isconcentrically positioned within and completely surrounded by the secondelongated member 42 that is formed as a sheath member. Here, core/sheathfiber 22 comprises 50 percent by weight of the core member and 50percent by weight of the sheath member.

Core/sheath fiber 23 comprises a first elongated member 43 positionedwithin and surrounded by a second elongated member 44. In the presentembodiment, however, the first elongated member 43 is formed as a coremember that is eccentrically positioned within the second elongatedmember 44 that is formed as a sheath member. Core/sheath fiber 23 maycomprise virtually any percentages by weight of the core member and thesheath member to provide desired thermal regulating and mechanicalproperties.

Tri-lobal core/sheath fiber 24 comprises a first elongated member 45positioned within and surrounded by a second elongated member 46. In thepresent embodiment, the first elongated member 45 is formed as a coremember that has a tri-lobal cross sectional shape. This core member isconcentrically positioned within the second elongated member 46 that isformed as a sheath member. Core/sheath fiber 23 may comprise virtuallyany percentages by weight of the core member and the sheath member toprovide desired thermal regulating and mechanical properties.

It should be recognized that a core member may, in general, have avariety of regular or irregular cross sectional shapes, such as, by wayof example and not by limitation, circular, multi-lobal, octagonal,oval, pentagonal, rectangular, square-shaped, trapezoidal, triangular,wedge-shaped, and so forth. While core/sheath fibers 21, 22, 23, and 24are shown with one core member positioned within and surrounded by asheath member, it should be recognized that two or more core members maybe positioned within and surrounded by a sheath member (e.g., in amanner similar to that shown for multi-component fiber 13). These two ormore core members may have the same or different cross sectional shapesor sizes. According to some embodiments of the invention, a core/sheathfiber comprises three or more elongated members arranged in acore-sheath configuration, wherein the elongated members are shaped asconcentric or eccentric longitudinal slices of the core/sheath fiber.

Right-hand column 30 of FIG. 1 illustrates a number of exemplaryside-by-side fibers in accordance with some embodiments of theinvention. In particular, side-by-side fibers 26, 27, 28, 29, and 34each comprises a plurality of elongated members arranged in aside-by-side configuration.

Side-by-side fiber 26 comprises a first elongated member 47 positionedadjacent and partially surrounded by a second elongated member 48. Inthe present embodiment, the elongated members 47 and 48 havehalf-circular cross sectional shapes. Here, side-by-side fiber 26comprises 50 percent by weight of the first elongated member 47 and 50percent by weight of the second elongated member 48. It should berecognized that the elongated members 47 and 48 may, alternatively or inconjunction, be characterized as being arranged in a segmented-pie or astriped configuration.

Side-by-side fiber 27 comprises a first elongated member 49 positionedadjacent and partially surrounded by a second elongated member 50. Inthe present embodiment, side-by-side fiber 27 comprises 20 percent byweight of the first elongated member 49 and 80 percent by weight of thesecond elongated member 50. It should be recognized that the elongatedmembers 49 and 50 may, alternatively or in conjunction, be characterizedas being arranged in a core-sheath configuration, wherein the firstelongated member 49 is eccentrically positioned with respect to andpartially surrounded by the second elongated member 50.

Side-by-side fibers 28 and 29 are two exemplary mixed-viscosity fibers.Each fiber comprises a first elongated member 51 or 53 having atemperature regulating material dispersed therein that is positionedadjacent and partially surrounded by a second elongated member 52 or 54.A mixed viscosity-fiber is typically considered to be a self-crimping orself-texturing fiber, wherein the fiber's crimping or texturing impartsloft, bulk, insulation, stretch, or other like properties to the fiber.Typically, a mixed-viscosity fiber comprises a plurality of elongatedmembers that are formed from different polymeric materials. For example,for side-by-side fiber 28, the first elongated member 51 may be formedfrom a first polymeric material, and the second elongated member 52 maybe formed from a second polymeric material that may differ in somefashion from the first polymeric material. In the present embodiment,the first and second polymeric materials may comprise polymers withdifferent viscosities or molecular weights (e.g., two polypropyleneswith different molecular weights or a polypropylene and a polyethylene,respectively). When side-by-side fiber 28 is drawn, uneven stresses maybe created between the two elongated members 51 and 52, and side-by-sidefiber 28 may crimp or bend. According to other embodiments of theinvention, the first and second polymeric materials may comprisepolymers having different degrees of crystallinity. For instance, thefirst polymeric material may have a lower degree of crystallinity thanthe second polymeric material. When side-by-side fiber 28 is drawn, thefirst and second polymeric materials may undergo different degrees ofcrystallization and orientation to “lock” an orientation and strengthinto the fiber 28. A sufficient degree of crystallization may be desiredto prevent or reduce reorientation of the fiber 28 during heattreatment. Side-by-side fibers 28 and 29 may comprise virtually anypercentages by weight of the first and second elongated members toprovide desired thermal regulating, mechanical, and self-crimping orself-texturing properties.

Side-by-side fiber 34 is an exemplary ABA fiber comprising a firstelongated member 55 positioned between and partially surrounded by asecond plurality of elongated members 56 and 56′. In the presentembodiment, the first elongated member 55 is formed from a firstpolymeric material that has a temperature regulating material dispersedtherein. Here, the second plurality of elongated members 56 and 56′ maybe formed from the first polymeric material or from a second polymericmaterial that may differ in some fashion from the first polymericmaterial. In general, the elongated members 56 and 56′ may have the sameor different cross sectional shapes or sizes (e.g., widths associatedwith the longitudinal slices). It should be recognized that theelongated members 55, 56, and 56′ may, alternatively or in conjunction,be characterized as being arranged in a striped configuration.

Turning next to FIG. 2, a three-dimensional view of an exemplarycore/sheath fiber 59 is illustrated. Core/sheath fiber 59 comprises anelongated and generally cylindrical core member 57 positioned within andsurrounded by an elongated and annular-shaped sheath member 58. In thepresent embodiment, the core member 57 extends through substantially thelength of the core/sheath fiber 59. The core member 57 has a temperatureregulating material 61 dispersed therein and is positioned within andcompletely surrounded or encased by the sheath member 58 that forms theexterior of the core/sheath fiber 59. In the present embodiment, thetemperature regulating material 61 comprises a plurality ofmicrocapsules containing a phase change material, and the microcapsulesmay be uniformly dispersed throughout the core member 57. Those ofordinary skill in the art will appreciate that, while it may bepreferred to have the microcapsules evenly dispersed within the coremember 57, this is not necessary in all applications. The core member 57may be concentrically or eccentrically positioned within the sheathmember 58, and core/sheath fiber 59 may comprise virtually anypercentages by weight of the core member 57 and the sheath member 58 toprovide desired thermal regulating and mechanical properties.

With reference to FIG. 3, a three-dimensional view of another exemplarycore/sheath fiber 60 is illustrated. As with core/sheath fiber 59,core/sheath fiber 60 comprises an elongated and generally cylindricalcore member 63 extending through substantially the length of thecore/sheath fiber 60. The core member 63 is positioned within andcompletely surrounded or encased by an elongated and annular-shapedsheath member 64 that forms the exterior of the core/sheath fiber 60.Here, a temperature regulating material 62 comprises a phase changematerial in a raw form (e.g., the phase change material isnon-encapsulated, i.e., not micro- or macroencapsulated), and the phasechange material may be uniformly dispersed throughout the core member63. Those of ordinary skill in the art will appreciate that, while itmay be preferred to have the phase change material evenly dispersedwithin the core member 63, this is not necessary in all applications. Inthe present embodiment shown in FIG. 3, the phase change material formsdistinct domains that are dispersed within the core member 63. Bysurrounding the core member 63, the sheath member 64 may serve toenclose the phase change material within the core member 63.Accordingly, the sheath member 64 may reduce or prevent loss or leakageof the phase change material during fiber processing or during end use.The core member 63 may be concentrically or eccentrically positionedwithin the sheath member 64, and core/sheath fiber 60 may comprisevirtually any percentages by weight of the core member 63 and the sheathmember 64 to provide desired thermal regulating and mechanicalproperties.

With reference to FIG. 4, a three-dimensional view of an exemplaryisland-in-sea fiber 70 is illustrated. Island-in-sea fiber 70 comprisesa plurality of elongated and generally cylindrical island members 72,73, 74, and 75 positioned within and completely surrounded or encased byan elongated sea member 71. In the present embodiment, the islandmembers 72, 73, 74, and 75 extend though substantially the length of theisland-in-sea fiber 70. While four island members are shown in thepresent embodiment, it should be recognized that island-in-sea fiber 70may comprise more or less islands members depending on the specificapplication of the island-in-sea fiber 70. The sea member 71 is formedof a sea polymeric material 82, and the island members 72, 73, 74, and75 are formed of island polymeric materials 76, 77, 78, and 79,respectively. The sea polymeric material 82 and the island polymericmaterials 76, 77, 78, and 79 may be the same or may differ from oneanother in some fashion. One or more temperature regulating materialsmay be dispersed within the island members 72, 73, 74, and 75. As shownin FIG. 4, island-in-sea fiber 70 comprises two different temperatureregulating materials 80 and 81. Island members 72 and 75 comprise thetemperature regulating material 80, while island members 73 and 74comprise the temperature regulating material 81. Here, the temperatureregulating materials 80 and 81 may each comprise a phase change materialin a raw form that forms distinct domains within respective islandmembers. By surrounding the island members 72, 73, 74, and 75, the seamember 71 may serve to enclose the phase change materials withinisland-in-sea fiber 70. Island-in-sea fiber 70 may comprise virtuallyany percentages by weight of the island members 72, 73, 74, and 75 andthe sea member 71 to provide desired thermal regulating and mechanicalproperties.

As discussed previously, a multi-component fiber according to someembodiments of the invention may comprise one or more temperatureregulating materials. A temperature regulating material typically willcomprise one or more phase change materials. In general, a phase changematerial may comprise any substance (or mixture of substances) that hasthe capability of absorbing or releasing thermal energy to reduce oreliminate heat flow at or within a temperature stabilizing range. Thetemperature stabilizing range may comprise a particular transitiontemperature or range of transition temperatures. A phase change materialused in conjunction with various embodiments of the invention preferablywill be capable of inhibiting a flow of thermal energy during a timewhen the phase change material is absorbing or releasing heat, typicallyas the phase change material undergoes a transition between two states(e.g., liquid and solid states, liquid and gaseous states, solid andgaseous states, or two solid states). This action is typicallytransient, e.g., will occur until a latent heat of the phase changematerial is absorbed or released during a heating or cooling process.Thermal energy may be stored or removed from the phase change material,and the phase change material typically can be effectively recharged bya source of heat or cold. By selecting an appropriate phase changematerial, the multi-component fiber may be designed for use in any oneof numerous products.

According to some embodiments of the invention, a phase change materialmay be a solid/solid phase change material. A solid/solid phase changematerial is a type of phase change material that typically undergoes atransition between two solid states (e.g., a crystalline ormesocrystalline phase transformation) and hence typically does notbecome a liquid during use.

Phase change materials that can be incorporated in multi-componentfibers in accordance with various embodiments of the invention include avariety of organic and inorganic substances. Exemplary phase changematerials include, by way of example and not by limitation, hydrocarbons(e.g., straight chain alkanes or paraffinic hydrocarbons, branched-chainalkanes, unsaturated hydrocarbons, halogenated hydrocarbons, andalicyclic hydrocarbons), hydrated salts (e.g., calcium chloridehexahydrate, calcium bromide hexahydrate, magnesium nitrate hexahydrate,lithium nitrate trihydrate, potassium fluoride tetrahydrate, ammoniumalum, magnesium chloride hexahydrate, sodium carbonate decahydrate,disodium phosphate dodecahydrate, sodium sulfate decahydrate, and sodiumacetate trihydrate), waxes, oils, water, fatty acids, fatty acid esters,dibasic acids, dibasic esters, 1-halides, primary alcohols, aromaticcompounds, clathrates, semi-clathrates, gas clathrates, anhydrides(e.g., stearic anhydride), ethylene carbonate, polyhydric alcohols(e.g., 2,2-dimethyl-1,3-propanediol,2-hydroxymethyl-2-methyl-1,3-propanediol, ethylene glycol, polyethyleneglycol, pentaerythritol, dipentaerythritol, pentaglycerine,tetramethylol ethane, neopentyl glycol, tetramethylol propane,2-amino-2-methyl-1,3-propanediol, monoaminopentaerythritol,diaminopentaerythritol, and tris(hydroxymethyl)acetic acid), polymers(e.g., polyethylene, polyethylene glycol, polyethylene oxide,polypropylene, polypropylene glycol, polytetramethylene glycol,polypropylene malonate, polyneopentyl glycol sebacate, polypentaneglutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate,polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyestersproduced by polycondensation of glycols (or their derivatives) withdiacids (or their derivatives), and copolymers, such as polyacrylate orpoly(meth)acrylate with alkyl hydrocarbon side chain or withpolyethylene glycol side chain and copolymers comprising polyethylene,polyethylene glycol, polyethylene oxide, polypropylene, polypropyleneglycol, or polytetramethylene glycol), metals, and mixtures thereof.

The selection of a phase change material will typically be dependentupon a desired transition temperature or a desired application of aresulting multi-component fiber. For example, a phase change materialhaving a transition temperature near room temperature may be desirablefor applications in which the resulting multi-component fiber isincorporated into apparel designed to maintain a comfortable temperaturefor a user.

A phase change material according to some embodiments of the inventionmay have a transition temperature ranging from about −5° to about 125°C. In one presently preferred embodiment useful for clothingapplications, the phase change material will have a transitiontemperature ranging from about 22° to about 40° C. or from about 22° toabout 28° C.

According to some embodiments of the invention, particularly usefulphase change materials include paraffinic hydrocarbons having between 10to 44 carbon atoms (i.e., C₁₀-C₄₄ paraffinic hydrocarbons). Table 1provides a list of exemplary C₁₃-C₂₈ paraffinic hydrocarbons that may beused as the phase change material in the multi-component fibersdescribed herein. The number of carbon atoms of a paraffinic hydrocarbontypically correlates with its melting point. For example, n-Octacosane,which contains twenty-eight straight chain carbon atoms per molecule,has a melting point of 61.4° C. By comparison, n-Tridecane, whichcontains thirteen straight chain carbon atoms per molecule, has amelting point of −5.5° C. According to an embodiment of the invention,n-Octadecane, which contains eighteen straight chain carbon atoms permolecule and has a melting point of 28.2° C., is particularly desirablefor clothing applications. TABLE 1 No. of Melting Carbon PointParaffinic Hydrocarbon Atoms (° C.) n-Octacosane 28 61.4 n-Heptacosane27 59.0 n-Hexacosane 26 56.4 n-Pentacosane 25 53.7 n-Tetracosane 24 50.9n-Tricosane 23 47.6 n-Docosane 22 44.4 n-Heneicosane 21 40.5 n-Eicosane20 36.8 n-Nonadecane 19 32.1 n-Octadecane 18 28.2 n-Heptadecane 17 22.0n-Hexadecane 16 18.2 n-Pentadecane 15 10.0 n-Tetradecane 14 5.9n-Tridecane 13 −5.5

Other useful phase change materials include polymeric phase changematerials having transition temperatures suitable for a desiredapplication of the multi-component fiber (e.g., from about 22° to about40° C. for clothing applications). A polymeric phase change material maycomprise a polymer (or mixture of polymers) having a variety of chainstructures that include one or more types of monomer units. Inparticular, polymeric phase change materials may include linearpolymers, branched polymers (e.g., star branched polymers, comb branchedpolymers, or dendritic branched polymers), or mixtures thereof. Apolymeric phase change material may comprise a homopolymer, a copolymer(e.g., terpolymer, statistical copolymer, random copolymer, alternatingcopolymer, periodic copolymer, block copolymer, radial copolymer, orgraft copolymer), or a mixture thereof. As one of ordinary skill in theart will understand, the reactivity and functionality of a polymer maybe altered by addition of a functional group such as, for example,amine, amide, carboxyl, hydroxyl, ester, ether, epoxide, anhydride,isocyanate, silane, ketone, and aldehyde. Also, a polymer comprising apolymeric phase change material may be capable of crosslinking,entanglement, or hydrogen bonding in order to increase its toughness orits resistance to heat, moisture, or chemicals.

According to some embodiments of the invention, a polymeric phase changematerial may be desirable as a result of having a higher molecularweight, larger molecular size, or higher viscosity relative tonon-polymeric phase change materials (e.g., paraffinic hydrocarbons). Asa result of this larger molecular size or higher viscosity, a polymericphase change material may exhibit a lesser tendency to leak from themulti-component fiber during processing or during end use. Whenincorporated within a core/sheath fiber or island-in-sea fiber, forexample, this larger molecular size or higher viscosity may prevent thepolymeric phase change material from flowing through a sheath member orsea member forming the exterior of the fiber. In addition to providingthermal regulating properties, a polymeric phase change material mayprovide improved mechanical properties (e.g., ductility, tensilestrength, and hardness) when incorporated in multi-component fibers inaccordance with various embodiments of the invention. If desired, apolymeric phase change material having a desired transition temperaturemay be combined with a polymeric material to form an elongated member.According to some embodiments of the invention, the polymeric phasechange material may provide adequate mechanical properties such that itmay be used to form the elongated member without requiring the polymericmaterial, thus allowing for a higher loading level of the polymericphase change material and improved thermal regulating properties.

For example, polyethylene glycols may be used as the phase changematerial in some embodiments of the invention. The number averagemolecular weight of a polyethylene glycol typically correlates with itsmelting point. For instance, a polyethylene glycol having a numberaverage molecular weight range of 570 to 630 (e.g., Carbowax 600) willhave a melting point of 20° C. to 25° C., making it desirable forclothing applications. Other polyethylene glycols that may be useful atother temperature stabilizing ranges include Carbowax 400 (melting pointof 4° to 8° C.), Carbowax 1500 (melting point of 44° to 48° C.), andCarbowax 6000 (melting point of 56° to 63° C.). Polyethylene oxideshaving a melting point in the range of 60° to 65° C. may also be used asphase change materials in some embodiments of the invention. Furtherdesirable phase change materials include polyesters having a meltingpoint in the range of 0° to 40° C. that may be formed, for example, bypolycondensation of glycols (or their derivatives) with diacids (ortheir derivatives). Table 2 sets forth melting points of exemplarypolyesters that may be formed with various combinations of glycols anddiacids. TABLE 2 Melting Point of Polyester Glycol Diacid (° C.)Ethylene glycol Carbonic 39 Ethylene glycol Pimelic 25 Ethylene glycolDiglycolic 17-20 Ethylene glycol Thiodivaleric 25-28 1,2-Propyleneglycol Diglycolic 17 Propylene glycol Malonic 33 Propylene glycolGlutaric 35-39 Propylene glycol Diglycolic 29-32 Propylene glycolPimelic 37 1,3-butanediol Sulphenyl divaleric 32 1,3-butanediol Diphenic36 1,3-butanediol Diphenyl methane-m,m′-diacid 38 1,3-butanedioltrans-H,H-terephthalic acid 18 Butanediol Glutaric 36-38 ButanediolPimelic 38-41 Butanediol Azelaic 37-39 Butanediol Thiodivaleric 37Butanediol Phthalic 17 Butanediol Diphenic 34 Neopentyl glycol Adipic 37Neopentyl glycol Suberic 17 Neopentyl glycol Sebacic 26 PentanediolSuccinic 32 Pentanediol Glutaric 22 Pentanediol Adipic 36 PentanediolPimelic 39 Pentanediol para-phenyl diacetic acid 33 PentanediolDiglycolic 33 Hexanediol Glutaric 28-34 Hexanediol 4-Octenedioate 20Heptanediol Oxalic 31 Octanediol 4-Octenedioate 39 Nonanediolmeta-phenylene diglycolic 35 Decanediol Malonic 29-34 DecanediolIsophthalic 34-36 Decanediol meso-tartaric 33 Diethylene glycol Oxalic10 Diethylene glycol Suberic 28-35 Diethylene glycol Sebacic 36-44Diethylene glycol Phthalic 11 Diethylene glycol trans-H,H-terephthalicacid 25 Triethylene glycol Sebacic 28 Triethylene glycol Sulphonyldivaleric 24 Triethylene glycol Phthalic 10 Triethylene glycol Diphenic38 para-dihydroxy-methyl Malonic 36 benzene meta-dihydroxy-methylSebacic 27 benzene meta-dihydroxy-methyl Diglycolic 35 benzene

According to some embodiments of the invention, a polymeric phase changematerial having a desired transition temperature may be formed byreacting a phase change material (e.g., an exemplary phase changematerial discussed above) with a polymer (or mixture of polymers). Thus,for example, n-octadecylic acid (i.e., stearic acid) may be reacted oresterified with polyvinyl alcohol to yield polyvinyl stearate, ordodecanoic acid (i.e., lauric acid) may be reacted or esterified withpolyvinyl alcohol to yield polyvinyl laurate. Various combinations ofphase change materials (e.g., phase change materials with one or morefunctional groups such as amine, carboxyl, hydroxyl, epoxy, silane,sulfuric, and so forth) and polymers may be reacted to yield polymericphase change materials having desired transition temperatures.

A phase change material can comprise a mixture of two or more substances(e.g., two or more of the exemplary phase change materials discussedabove). By selecting two or more different substances (e.g., twodifferent paraffinic hydrocarbons) and forming a mixture thereof, atemperature stabilizing range can be adjusted over a wide range for anyparticular application of the multi-component fiber. According to someembodiments of invention, the mixture of two or more differentsubstances may exhibit two or more distinct transition temperatures or asingle modified transition temperature when incorporated in themulti-component fiber.

According to some embodiments of the invention, the temperatureregulating material may comprise a phase change material in a raw form(e.g., the phase change material is non-encapsulated, i.e., not micro-or macroencapsulated). During manufacture of the multi-component fiber,the phase change material in the raw form may be provided as a solid ina variety of forms (e.g., bulk form, powders, pellets, granules, flakes,and so forth) or as a liquid in a variety of forms (e.g., molten form,dissolved in a solvent, and so forth).

According to other embodiments of the invention, the temperatureregulating material may further comprise a containment structure thatencapsulates, contains, surrounds, absorbs, or reacts with a phasechange material. This containment structure may facilitate handling ofthe phase change material while offering a degree of protection to thephase change material during manufacture of the multi-component fiber ora product made therefrom (e.g., protection from high temperatures orshear forces). Moreover, the containment structure may serve to reduceor prevent leakage of the phase change material from the multi-componentfiber during use. According to some embodiments of the invention, use ofthe containment structure may be desirable, but not required, wherein afirst elongated member having the phase change material dispersedtherein is not completely surrounded by a second elongated member.

For instance, the temperature regulating material may comprise aplurality of microcapsules that contain a phase change material, and themicrocapsules may be uniformly, or non-uniformly, dispersed within atleast one of the elongated members. The microcapsules may be formed asshells enclosing the phase change material and may comprise individualmicrocapsules formed in a variety regular or irregular shapes (e.g.,spherical, ellipsoidal, and so forth) and sizes. The individualmicrocapsules may have the same or different shapes or sizes. Accordingto some embodiments of the invention, the microcapsules may have amaximum linear dimension (e.g., diameter) ranging from about 0.01 toabout 100 microns. In one presently preferred embodiment, themicrocapsules will have a generally spherical shape and will have amaximum linear dimension (e.g., diameter) ranging from about 0.5 toabout 3 microns. Other examples of the containment structure mayinclude, by way of example and not by limitation, silica particles(e.g., precipitated silica particles, fumed silica particles, andmixtures thereof), zeolite particles, carbon particles (e.g., graphiteparticles, activated carbon particles, and mixtures thereof), andabsorbent materials (e.g., absorbent polymeric materials, superabsorbentmaterials, cellulosic materials, poly(meth)acrylate materials, metalsalts of poly(meth)acrylate materials, and mixtures thereof). Forinstance, the temperature regulating material may comprise silicaparticles, zeolite particles, carbon particles, or an absorbent materialimpregnated with a phase change material.

According to some embodiments of the invention, one or more elongatedmembers may each comprise up to about 100 percent by weight of thetemperature regulating material. Typically, an elongated member maycomprise up to about 90 percent by weight of the temperature regulatingmaterial (e.g., up to about 50 percent or up to about 25 percent byweight of the temperature regulating material). In some presentlypreferred embodiments, an elongated member may comprise from about 5percent to about 70 percent by weight of the temperature regulatingmaterial. Thus, in one embodiment, an elongated member may comprise 60percent by weight of the temperature regulating material, and in otherembodiments, the elongated member may comprise from about 10 percent toabout 30 percent or from about 15 percent to about 25 percent by weightof the temperature regulating material.

As discussed previously, a multi-component fiber according to someembodiments of the invention may comprise a plurality of elongatedmembers. These elongated members may be formed from the same ordifferent polymeric materials. According to some embodiments of theinvention, the elongated members may include a first elongated member(or a first plurality of elongated members) formed from a firstpolymeric material that has a temperature regulating material dispersedtherein. In addition, the elongated members may include a secondelongated member (or a second plurality of elongated members) formedfrom a second polymeric material that may differ in some fashion fromthe first polymeric material. It should be recognized that the elongatedmembers may be formed from the same polymeric material, in which casethe first and second polymeric materials will be the same. According tosome embodiments of the invention, the temperature regulating materialmay comprise a polymeric phase change material that provides adequatemechanical properties such that it may be used to form the firstelongated member (or the first plurality of elongated members) withoutrequiring the first polymeric material.

In general, a polymeric material (e.g., the first polymeric material orthe second polymeric material) may comprise any polymer (or mixture ofpolymers) that has the capability of being formed into an elongatedmember. According to some embodiments of the invention, an elongatedmember may be formed from any fiber-forming polymer (or mixture offiber-forming polymers). According to embodiments of the inventionwherein a melt spinning process is used to form the multi-componentfiber, a polymeric material may comprise a thermoplastic polymer (ormixture of thermoplastic polymers) (i.e., one that can be heated to forma melt and subsequently shaped or molded to form an elongated member).According to other embodiments of the invention, a polymeric materialmay comprise an elastomeric polymer (or mixture of elastomericpolymers).

A polymeric material may comprise a polymer (or mixture of polymers)having a variety of chain structures that include one or more types ofmonomer units. In particular, a polymeric material may comprise a linearpolymer, a branched polymer (e.g., star branched polymer, comb branchedpolymer, or dendritic branched polymer), or a mixture thereof. Apolymeric material may comprise a homopolymer, a copolymer (e.g.,terpolymer, statistical copolymer, random copolymer, alternatingcopolymer, periodic copolymer, block copolymer, radial copolymer, orgraft copolymer), or a mixture thereof. As one of ordinary skill in theart will understand, the reactivity and functionality of a polymer maybe altered by addition of a functional group such as, for example,amine, amide, carboxyl, hydroxyl, ester, ether, epoxide, anhydride,isocyanate, silane, ketone, and aldehyde. Also, a polymer comprising apolymeric material may be capable of crosslinking, entanglement, orhydrogen bonding in order to increase its toughness or its resistance toheat, moisture, or chemicals.

Exemplary polymers that may be used to form an elongated memberaccording to various embodiments of the invention include, by way ofexample and not by limitation, polyamides (e.g., Nylon 6, Nylon 6/6,Nylon 12, polyaspartic acid, polyglutamic acid, and so forth),polyamines, polyimides, polyacrylics (e.g., polyacrylamide,polyacrylonitrile, esters of methacrylic acid and acrylic acid, and soforth), polycarbonates (e.g., polybisphenol A carbonate, polypropylenecarbonate, and so forth), polydienes (e.g., polybutadiene, polyisoprene,polynorbornene, and so forth), polyepoxides, polyesters (e.g.,polyethylene terephthalate, polybutylene terephthalate, polytrimethyleneterephthalate, polycaprolactone, polyglycolide, polylactide,polyhydroxybutyrate, polyhydroxyvalerate, polyethylene adipate,polybutylene adipate, polypropylene succinate, and so forth), polyethers(e.g., polyethylene glycol (polyethylene oxide), polybutylene glycol,polypropylene oxide, polyoxymethylene (paraformaldehyde),polytetramethylene ether (polytetrahydrofuran), polyepichlorohydrin, andso forth), polyfluorocarbons, formaldehyde polymers (e.g.,urea-formaldehyde, melamine-formaldehyde, phenol formaldehyde, and soforth), natural polymers (e.g., cellulosics, chitosans, lignins, waxes,and so forth), polyolefins (e.g., polyethylene, polypropylene,polybutylene, polybutene, polyoctene, and so forth), polyphenylenes(e.g., polyphenylene oxide, polyphenylene sulfide, polyphenylene ethersulfone, and so forth), silicon containing polymers (e.g., polydimethylsiloxane, polycarbomethyl silane, and so forth), polyurethanes,polyvinyls (e.g., polyvinyl butyral, polyvinyl alcohol, esters andethers of polyvinyl alcohol, polyvinyl acetate, polystyrene,polymethylstyrene, polyvinyl chloride, polyvinyl pryrrolidone,polymethyl vinyl ether, polyethyl vinyl ether, polyvinyl methyl ketone,and so forth), polyacetals, polyarylates, and copolymers (e.g.,polyethylene-co-vinyl acetate, polyethylene-co-acrylic acid,polybutylene terephthalate-co-polyethylene terephthalate,polylauryllactam-block-polytetrahydrofuran, and so forth).

According to some embodiments of the invention, the first polymericmaterial may comprise a polymer (or mixture of polymers) thatfacilitates dispersing or incorporating the temperature regulatingmaterial within the first elongated member (or the first plurality ofelongated members). According to some embodiments of the invention, thefirst polymeric material may comprise a polymer (or mixture of polymers)that is compatible or miscible with or has an affinity for thetemperature regulating material. In some embodiments of the invention,this affinity may depend on, by way of example and not by limitation,similarity of solubility parameters, polarities, hydrophobiccharacteristics, or hydrophilic characteristics of the first polymericmaterial and the temperature regulating material. Such affinity mayfacilitate dispersion of the temperature regulating material in anintermediate molten or liquid form of the first polymeric materialduring manufacture of the multi-component fiber and, thus, ultimatelymay facilitate incorporation of more uniform or greater amounts orloading level of a phase change material in the multi-component fiber.In embodiments where the temperature regulating material furthercomprises a containment structure, the first polymeric material maycomprise a polymer (or mixture of polymers) selected for its affinityfor the containment structure in conjunction with or as an alternativeto its affinity for the phase change material. For instance, if thetemperature regulating material comprises a plurality of microcapsulescontaining the phase change material, a polymer (or mixture of polymers)may be selected having an affinity for the microcapsules (e.g., for amaterial or materials of which the microcapsules are formed). Forinstance, some embodiments of the invention may select the firstpolymeric material to comprise the same or a similar polymer as apolymer comprising the microcapsules (e.g., if the microcapsulescomprise nylon shells, the first polymeric material may be selected tocomprise nylon). Such affinity may facilitate dispersion of themicrocapsules containing the phase change material in an intermediatemolten or liquid form of the first polymeric material and, thus,ultimately facilitates incorporation of more uniform or greater amountsor loading level of the phase change material in the multi-componentfiber. In one presently preferred embodiment of the invention, the firstpolymeric material may be selected to be sufficiently non-reactive withthe temperature regulating material so that a desired temperaturestabilizing range is maintained when the temperature regulating materialis dispersed within the first polymeric material.

According to some embodiments of the invention, the first polymericmaterial may comprise a polymer (or mixture of polymers) that has aslight or partial compatibility or miscibility with or affinity for thetemperature regulating material (e.g., a semi-miscible polymer). Suchpartial affinity may be adequate to facilitate dispersion of thetemperature regulating material and to facilitate processing at highertemperatures and during a melt spinning process. At lower temperaturesand shear conditions and once the multi-component fiber has been formed,this partial affinity may allow the temperature regulating material toseparate out. For embodiments of the invention wherein a phase changematerial in a raw form is used, this partial affinity may lead toinsolubilization of the phase change material and increased phase changematerial domain formation within the multi-component fiber. According tosome embodiments of the invention, domain formation may lead to animproved thermal regulating property by facilitating transition of thephase change material between two states. In addition, domain formationmay serve to reduce or prevent loss or leakage of the phase changematerial from the multi-component fiber during processing or during use.

For instance, certain phase change materials such as paraffinichydrocarbons may be compatible with polymeric materials comprisingpolyethylene or polyethylene-co-vinyl acetate at lower concentrations ofthe phase change materials or when the temperature is above a criticalsolution temperature. Mixing of a paraffinic hydrocarbon (or a mixtureof paraffinic hydrocarbons) and polyethylene or polyethylene-co-vinylacetate may be achieved at higher temperatures and higher concentrationsof the paraffinic hydrocarbon to produce a homogenous blend that may beeasily controlled, pumped, and processed in a melt spinning process.Once a multi-component fiber has been formed and has cooled, theparaffinic hydrocarbon may become insoluble and may separate out intodistinct domains. These domains may allow for pure melting orcrystallization of the paraffinic hydrocarbon for an improved thermalregulating property. In addition, these domains may serve to reduce orprevent loss or leakage of the paraffinic hydrocarbon. According to someembodiments of the invention, the first polymeric material may comprisepolyethylene-co-vinyl acetate having between about 5 and about 90percent by weight of the vinyl acetate, and, according to otherembodiments of the invention, the vinyl acetate content is between about5 and about 50 percent by weight. In one presently preferred embodiment,the vinyl acetate content is desirably between 18 to 25 percent byweight. This content of the vinyl acetate may allow for temperaturemiscibility control when mixing the paraffinic hydrocarbon and thepolyethylene-co-vinyl acetate to form a blend. In particular, this vinylacetate content may allow for excellent miscibility at highertemperatures, thus facilitating melt spinning process stability andcontrol due to homogeneity of the blend. At lower temperatures (e.g.,room temperature or normal commercial fabric use temperatures), thepolyethylene-co-vinyl acetate is semi-miscible with the paraffinichydrocarbon, thus allowing for separation and micro-domain formation ofthe paraffinic hydrocarbon.

The first polymeric material may serve as a carrier for the temperatureregulating material as the multi-component fiber is being formed inaccordance with some embodiments of the invention. In addition, thefirst polymeric material may facilitate maintaining integrity of thefirst elongated member (or the first plurality of elongated members)during fiber processing and provide enhanced mechanical properties tothe resulting multi-component fiber.

According to an embodiment of the invention, the first polymericmaterial may comprise a low molecular weight polymer (or a mixture oflow molecular weight polymers). A low molecular weight polymer typicallyhas a low viscosity when heated to form a melt, which low viscosity mayfacilitate dispersion of the temperature regulating material in themelt. As one of ordinary skill in the art will understand, some polymersmay be provided in a variety of forms having different molecularweights, since the molecular weight of a polymer may be determined byconditions used for manufacturing the polymer. Accordingly, as usedherein, the term “low molecular weight polymer” may refer to a lowmolecular weight form of a polymer (e.g., a low molecular weight form ofan exemplary polymer discussed previously), and the term “molecularweight” may refer to a number average molecular weight, weight averagemolecular weight, or melt index of the polymer. For instance, apolyethylene having a number average molecular weight of about 20,000(or less) may be used as the low molecular weight polymer in anembodiment of the invention. It should be recognized that a molecularweight or range of molecular weights associated with a low molecularweight polymer may depend on the particular polymer selected (e.g.,polyethylene) or on the method or equipment used to disperse thetemperature regulating material in a melt of the low molecular weightpolymer.

According to another embodiment of the invention, the first polymericmaterial may comprise a mixture of a low molecular weight polymer and ahigh molecular weight polymer. A high molecular weight polymer typicallyhas enhanced physical properties (e.g., mechanical properties) but mayhave a high viscosity when heated to form a melt. As used herein, theterm “high molecular weight polymer” may refer to a high molecularweight form of a polymer (e.g., a high molecular weight form of anexemplary polymer discussed previously). A low molecular weight polymeror a high molecular weight polymer may be selected to be compatible ormiscible with or to have an affinity for one another. Such affinity mayfacilitate forming a mixture of the low molecular weight polymer, thehigh molecular weight polymer, and the temperature regulating materialduring manufacture of the multi-component fiber and, thus, ultimatelyfacilitates incorporation of more uniform or greater amounts or loadinglevel of the phase change material in the multi-component fiber.According to some embodiments of the invention, the low molecular weightpolymer serves as a compatibilizing link between the high molecularweight polymer and the temperature regulating material to therebyfacilitate incorporating the temperature regulating material in themulti-component fiber.

According to some embodiments of the invention, an elongated member maytypically comprise from about 10 percent to about 30 percent by weightof the temperature regulating material with the remaining portion of theelongated member comprising a low molecular weight polymer and a highmolecular weight polymer. For example, in one presently preferredembodiment, the elongated member may comprise 15 percent by weight ofthe low molecular weight polymer, 70 percent by weight of the highmolecular weight polymer, and 15 percent by weight of the temperatureregulating material.

According to some embodiments of the invention, the second polymericmaterial may comprise a polymer (or mixture of polymers) that has orprovides one or more desired physical properties for the multi-componentfiber. Exemplary desired physical properties include, by way of exampleand not by limitation, mechanical properties (e.g., ductility, tensilestrength, and hardness), thermal properties (e.g., thermoformability),and chemical properties (e.g., reactivity). The second polymericmaterial may comprise a polymer (or mixture of polymers) selected tocompensate for any deficiencies (e.g., mechanical or thermaldeficiencies) of the first polymeric material or of the first elongatedmember (or the first plurality of elongated members), such as due to ahigh loading level of the temperature regulating material. According tosome embodiments of the invention, the second polymeric materialoperates to improve the multi-component fiber's overall physicalproperties (e.g., mechanical properties) and the multi-component fiber'sprocessability (e.g., by facilitating its formation via a melt spinningprocess). The second polymeric material may serve to enclose thetemperature regulating material that comprises the first elongatedmember (or the first plurality of elongated members). Accordingly, thesecond polymeric material may allow for the use of a first polymericmaterial or of a temperature regulating material that is not optimizedfor high temperature and high shear fiber processing. In addition, thesecond polymeric material may reduce or prevent loss or leakage of aphase change material during fiber processing or during end use.According to some embodiments of the invention, the second polymericmaterial may be sufficiently non-reactive with the temperatureregulating material to maintain a desired temperature stabilizing rangeof the temperature regulating material.

According to an embodiment of the invention, the second polymericmaterial may comprise a high molecular weight polymer. As discussedpreviously, a high molecular weight polymer typically has enhancedphysical properties (e.g., mechanical properties) and may be selected tobe a high molecular weight form of a polymer (e.g., a high molecularweight form of an exemplary polymer discussed previously).

According to some presently preferred embodiments of the invention, thesecond polymeric material may comprise a polyester due, in part, to itsexcellent processability, properties imparted to a resulting fiber, andits resistance to certain phase change materials such as paraffinichydrocarbons to reduce or prevent loss or leakage of these phase changematerials. According to an embodiment of the invention, the polyestermay have a number average molecular weight of about 20,000 (or more).

At this point, those of ordinary skill in the art can appreciate anumber of advantages associated with various embodiments of theinvention. For instance, a multi-component fiber in accordance withvarious embodiments of the invention can comprise high loading levels ofone or more phase change materials within a first elongated member (or afirst plurality of elongated members). According to some embodiments ofthe invention, a high loading level can be provided because a secondelongated member (or a second plurality of elongated members) surroundsthe first elongated member (or the first plurality of elongatedmembers). The second elongated member may comprise a polymer (or mixtureof polymers) selected to compensate for any deficiencies (e.g.,mechanical or thermal deficiencies) associated with the first elongatedmember, such as due to the high loading level of the phase changematerial. Moreover, the second elongated member may comprise a polymer(or mixture of polymers) selected to improve the fiber's overallphysical properties (e.g., mechanical properties) and the fiber'sprocessability (e.g., by facilitating its formation via a melt spinningprocess). By surrounding the first elongated member, the secondelongated member may serve to enclose the phase change material withinthe multi-component fiber to reduce or prevent loss or leakage of thephase change material.

Multi-component fibers in accordance with various embodiments of theinvention can have virtually any proportion of the fiber's total weightcomprising a first elongated member (or a first plurality of elongatedmembers) that includes a temperature regulating material relative to asecond elongated member (or a second plurality of elongated members). Byway of example and not by limitation, when a thermal regulating propertyof a multi-component fiber is a controlling consideration, a largerproportion of the multi-component fiber may comprise a first elongatedmember that includes a temperature regulating material. On the otherhand, when the physical properties of the multi-component fiber (e.g.,mechanical properties) are a controlling consideration, a largerproportion of the multi-component fiber may comprise a second elongatedmember that does not include the temperature regulating material.Alternatively, when balancing thermal regulating and physical propertiesof the multi-component fiber, it may be desirable that the secondelongated member includes the same or a different temperature regulatingmaterial.

A multi-component fiber in accordance with some embodiments of theinvention may comprise from about 1 percent up to about 99 percent byweight of a first elongated member (or a first plurality of elongatedmembers). Typically, a multi-component fiber according to an embodimentof the invention may comprise from about 10 percent to about 90 percentby weight of a first elongated member (or a first plurality of elongatedmembers). For instance, an embodiment of a core/sheath fiber maycomprise 90 percent by weight of a core member and 10 percent by weightof a sheath member. For this embodiment, the core member may comprise 60percent by weight of a temperature regulating material, such that thecore/sheath fiber comprises 54 percent by weight of the temperatureregulating material. Another embodiment of the core/sheath fiber maycomprise up to about 50 percent by weight of the core member, which inturn may comprise up to about 50 percent by weight of a temperatureregulating material. Utilizing such weight percentages provides thecore/sheath fiber with up to about 25 percent by weight of thetemperature regulating material and provides effective thermalregulating and mechanical properties for the core/sheath fiber. Itshould be recognized that the percent by weight of an elongated memberrelative to a total weight of the multi-component fiber may be varied,for example, by adjusting a cross sectional area of the elongated memberor by adjusting the extent to which the elongated member extends throughthe length of the multi-component fiber.

Multi-component fibers in accordance with various embodiments of theinvention may be manufactured using a variety methods, such as, forexample, using a melt spinning process or a solution spinning process(wet or dry). For either process, multi-component fibers may be formedby extruding materials through a plurality of orifices in a spinneret toform fibers that emerge from the orifices. As used herein, the term“spinneret” may refer to a portion of a fiber extrusion apparatus thatdelivers one or more polymeric materials and one or more temperatureregulating materials through orifices for extrusion into an outsideenvironment. A typical spinneret may comprise from 1 to 5000 orificesper meter of length of the spinneret. The spinneret may be implementedwith holes drilled or etched through a plate or with any other structurecapable of issuing desired fibers.

In a melt spinning process, one or more polymeric materials and one ormore temperature regulating materials forming the multi-component fibersmay be delivered to the orifices of the spinneret in a molten state.Prior to passing through the orifices, a temperature regulating materialmay be mixed with a first polymeric material to form a blend. As aresult of mixing, the temperature regulating material may be dispersedwithin and at least partially enclosed by the first polymeric material.Portions of the temperature regulating material that are not enclosed bythe first polymeric material may be enclosed by a second polymericmaterial upon emerging from the spinneret to reduce or prevent loss orleakage of the temperature regulating material from the resultingmulti-component fibers. The blend and the second polymeric material maybe combined and directed through each orifice in various configurationsto form a first elongated member (or a first plurality of elongatedmembers) and a second elongated member (or a second plurality ofelongated members), respectively, thus forming a multi-component fiber.For example, the blend may be directed through the orifices to form coremembers of core/sheath fibers or island members of island-in-sea fibers,and the second polymeric material may be directed through the orificesto form sheath members of core/sheath fibers or sea members ofisland-in-sea fibers.

According to some embodiments of the invention, multi-component fibersmay be formed using pellets comprising the first polymeric material andthe temperature regulating material. The pellets may, for example,comprise a solidified melt mixture of the temperature regulatingmaterial, a low molecular weight polymer, and a high molecular weightpolymer. According to other embodiments of the invention, the pelletsmay be formed from the first polymeric material, and the pellets may beimpregnated or imbibed with a phase change material. The pellets may bemelted to form a blend and processed along with the second polymericmaterial as discussed above to form multi-component fibers.

In a solution spinning process, one or more polymeric materials and oneor more temperature regulating materials forming the multi-componentfibers may be dissolved in a solvent prior to passing through theorifices of the spinneret. In a wet spinning process, the spinneret maybe submerged in a chemical bath such that, upon exiting the spinneret,the materials precipitate from solution and form a solid fiber. In a dryspinning process, the materials may emerge from the spinneret in air andsolidify due to the solvent (e.g., acetone) evaporating in air.

For either process, it should be recognized that the first polymericmaterial need not be used for certain applications. For instance, thetemperature regulating material may comprise a polymeric phase changematerial having a desired transition temperature and providing adequatemechanical properties when incorporated in the multi-component fibers.Thus, the temperature regulating material and the second polymericmaterial may be combined and directed through each orifice in variousconfigurations to form a first elongated member (or a first plurality ofelongated members) and a second elongated member (or a second pluralityof elongated members), respectively. For example, the temperatureregulating material may be directed through the orifices to form coremembers of core/sheath fibers or island members of island-in-sea fibers,and the second polymeric material may be directed through the orificesto form sheath members of core/sheath fibers or sea members ofisland-in-sea fibers.

After emerging from the spinneret, multi-component fibers may be drawnor stretched utilizing a godet or an aspirator. For example,multi-component fibers emerging from the spinneret in a melt spinningprocess may form a vertically oriented curtain of downwardly movingfibers that are at least partially quenched before entering a long,slot-shaped air aspirator positioned below the spinneret. The aspiratormay introduce a rapid, downwardly moving air stream produced bycompressed air from one or more air aspirating jets. The air stream maycreate a drawing force on the fibers, causing them to be drawn betweenthe spinneret and the air jet and attenuating the fibers. During thisportion of the manufacturing process, the polymeric materials formingthe multi-component fibers are typically solidifying.

Once formed, multi-component fibers may be further processed fornumerous fiber applications known in the art. In particular,multi-component fibers may be subjected to, by way of example and not bylimitation, woven, non-woven, knitting, or weaving processes to formvarious types of plaited, braided, twisted, felted, knitted, woven, ornon-woven fabrics. For example, multi-component fibers may be wound on abobbin or spun into a yarn and then utilized in various conventionalknitting or weaving processes. As another example, multi-componentfibers may be randomly laid on a forming surface (e.g., a movingconveyor screen belt such as a Fourdrinier wire) to form a continuous,non-woven web of fibers. According to an embodiment of the invention,multi-component fibers may be cut into short staple fibers prior toforming the web. One potential advantage of employing staple fibers isthat a more isotropic non-woven web may be formed, since the staplefibers may be oriented in the web more randomly than longer or uncutfibers (e.g., continuous fibers). The web may then be bonded using anyconventional method (e.g., a spunbond process) to form a stable,non-woven fabric for use in manufacturing a variety of textiles. Anexemplary bonding method involves lifting the web from the moving screenbelt and passing the web through two heated calender rolls. If desired,one of the rolls may be embossed to cause the web to be bonded innumerous spots. Air carded or spun-laid webs may also be formed frommulti-component fibers according to some embodiments of the invention.

It should be recognized that fabrics may be formed from multi-componentfibers comprising two or more different temperature regulatingmaterials. According to some embodiments of the invention, suchcombination of temperature regulating materials may exhibit two or moredistinct transition temperatures. For instance, a fabric for use inmanufacturing a glove may be formed from multi-component fiberscomprising phase change materials A and B. Phase change material A mayhave a melting point of about 5° C., and phase change material B mayhave a melting point of about 75° C. This combination of phase changematerials in the multi-component fibers may provide the glove withenhanced thermal regulating properties in cold environments (e.g.,outdoor use during winter conditions) as well as warm environments(e.g., when handling heated objects such as oven trays). In addition,fabrics may be formed from two or more types of multi-component fibersthat differ in some fashion (e.g., formed with different configurationsor comprising different temperature regulating materials). For example,a fabric may be formed from a certain percentage of core/sheath fiberscomprising a first temperature regulating material and a remainingpercentage of core/sheath fibers comprising a second temperatureregulating material. This combination of core/sheath fibers may providethe fabric with enhanced thermal regulating properties in differentenvironments (e.g., cold and warm).

Turning next to FIG. 5, an exemplary fiber extrusion apparatus 110 forforming multi-component fibers 134 in accordance with an embodiment ofthe invention is illustrated. The apparatus 110 may be used to form themulti-component fibers 134 via a melt spinning process. In addition, theapparatus 110 may be used to subject the formed multi-component fibers134 to a spunbond process to produce a non-woven fabric having desiredthermal regulating properties.

The apparatus 110 includes a spin pack 128 for extruding and forming themulti-component fibers 134. As used herein, the term “spin pack” mayrefer to an assembly for processing one or more polymeric materials andone or more temperature regulating materials to produce extruded fibers.According to some embodiments of the invention, a spin pack may includea filtration system, a distribution system, and a spinneret. Exemplaryspin packs are described in Hills, U.S. Pat. No. 5,162,074, entitled“Method of Making Plural Component Fibers” and references cited therein,the disclosures of which are incorporated herein by reference in theirentirety. In the present embodiment, the spin pack 128 provides a flowpath for two or more molten polymeric materials, and the multi-componentfibers 134 may emerge from spinneret 130 having one or moreconfigurations (e.g., core-sheath or island-in-sea configurations).

As shown in FIG. 5, apparatus 110 also includes hoppers 112 and 114 thatreceive a polymeric material A and a polymeric material B, respectively.Polymeric materials A and B may be provided in the form of a liquid orsolid (e.g., as pellets) and are respectively fed from hoppers 112 and114 into screw extruders 116 and 118. If initially provided in solidform, polymeric materials A and B typically melt as they are conveyedtowards heated pipes 120 and 122. A temperature regulating material Cmay be added to and mixed with polymeric material B at one or morelocations along apparatus 110 to form a blend prior to encounteringpolymeric material A at the spinneret 130. FIG. 5 shows variousexemplary locations for adding temperature regulating material C topolymeric material B in apparatus 110. For example, temperatureregulating material C may be added at location 113 to the hopper 114, atlocation 119 to the screw extruder 118, or at location 127 to the spinpack 128. It should be recognized that temperature regulating material Cmay be added to polymeric material B to form a blend, and this blend maybe provided in the form of a liquid or solid (e.g., as pellets) and thenfed into the hopper 114. Alternatively or in conjunction, temperatureregulating material C (or another temperature regulating material havingsomewhat different properties) may be added to and mixed with polymericmaterial A at one or more locations along apparatus 110 to form a blend.According to some embodiments of the invention, temperature regulatingmaterial C may comprise a polymeric phase change material that providesadequate mechanical properties when incorporated in the multi-componentfibers 134. For such embodiments of the invention, polymeric material Bmay be omitted, and temperature regulating material C may be simplyadded at location 113 to the hopper 114 and combined with polymericmaterial A at the spinneret 130 to form the multi-component fibers 134.

In the embodiment of the invention shown in FIG. 5, mixing oftemperature regulating material C with polymeric material B may beaccomplished in either, or both, a static or dynamic fashion. Dynamicmixing may occur by any mechanical method that effectively agitates ormixes temperature regulating material C with polymeric material B toform the blend, such as, for example, by using the screw extruder 118.For example, when temperature regulating material C is added to thehopper 114 or to the screw extruder 118, dynamic mixing occurs, and aliquid stream of the blend is moved within the screw extruder 118towards the heated pipe 122.

In contrast to dynamic mixing, static mixing typically need not utilizeany mechanical agitating or mixing methods. According to someembodiments of the invention, static mixing may be effected byintersecting pathways of two or more traveling liquid streams ofdifferent materials a sufficient number of times to achieve desiredmixing. An exemplary static mixer that may be used according to anembodiment of the invention is described in Haggard et al., U.S. Pat.No. 5,851,562, entitled “Instant Mixer Spin Pack”, the disclosure ofwhich is incorporated herein by reference in its entirety. Static mixingof temperature regulating material C with polymeric material B may occurwithin the spin pack 128 or at various other locations within theapparatus 110 prior to combining with polymeric material A at thespinneret 130. For example, temperature regulating material C may beadded at location 121 and statically mixed with polymeric material B asit travels within the heated pipe 122. In particular, a first liquidstream of temperature regulating material C may be intersected with asecond liquid stream of polymeric material B to form the desired blendin a resulting liquid stream. If desired, the resulting liquid streammay be further subjected to either, or both, static or dynamic mixingprior to combining with polymeric material A at the spinneret 130.

With reference to FIG. 5, liquid streams of polymeric material A and theblend may respectively flow through the heated pipes 120 and 122 tometering pumps 124 and 126, which feed the two liquid streams to thespin pack 128. The spin pack 128 has suitable internal componentscapable of forming the multi-component fibers 134 having a desiredconfiguration (e.g., a core-sheath or island-in-sea configuration). Inthe apparatus 110 of FIG. 5, the liquid streams are combined in the spinpack 128 such that polymeric material A surrounds the blend. The spinpack 128 includes the spinneret 130 with orifices 132 that form themulti-component fibers 134 extruded therethrough. An array of themulti-component fibers 134 exit the spinneret 130 and are pulleddownward and attenuated by an aspirator 136. The aspirator 136 is fed bycompressed air or steam from pipe 138. The aspirator 136 may be, forexample, of the gun type or of the slot type and, if desired, may extendacross the full width of the fiber array, e.g., in the directioncorresponding to the width of a web to be formed from themulti-component fibers 134.

It should be recognized that a plurality of separate blends may beformed, wherein each blend comprises one or more temperature regulatingmaterials and one or more polymeric materials. The separate blends maydiffer from one another in some fashion. For instance, the separateblends may comprise different temperature regulating materials ordifferent polymeric materials. Once formed, the separate blends may becombined with polymeric material A in the spin pack 128 such thatpolymeric material A surrounds the plurality of separate blends. Theseparate blends and polymeric material A may then be extruded from thespinneret 130 so as to form multi-component fibers having a desiredconfiguration (e.g., an island-in-sea configuration). According to anembodiment of the invention, an outer member (e.g., a sea member) may beformed of polymeric material A and may surround a plurality of innermembers (e.g., island members) formed of the plurality of separateblends.

With reference to FIG. 5, the aspirator 136 delivers attenuatedmulti-component fibers 140 onto a web-forming screen belt 142, which issupported and driven by rolls 144, 146, and 150. A suction box 148 maybe connected to a fan (not shown in FIG. 5) to pull ambient air throughthe screen belt 142 to cause the attenuated multi-component fibers 140to form a non-woven web on the screen belt 142. The resulting non-wovenweb can then be further processed to form textiles, apparel, or otherproducts that are endowed with thermal regulating properties.

EXAMPLES

The following examples describe specific aspects of the invention toillustrate and provide a description of the invention for those ofordinary skill in the art. The examples should not be construed aslimiting the invention, as the examples merely provide specificmethodology useful in understanding and practicing the invention.

Example 1

About five pounds of a low molecular weight polyethylene homopolymer(AC-16 polyethylene, drop point 102° C., manufactured by HoneywellSpecialty Chemical) was added to a wet flushing apparatus, and thehomopolymer was slowly melted and mixed at about 110° to about 130° C.Once the homopolymer was melted, about eight pounds of a wet cake wasslowly added to the molten homopolymer over about a 30 minute timeperiod to form a first blend. The wet cake comprised water-wettedmicrocapsules containing a phase change material (micro PCM lot #M45-22, 63.2 percent by weight of microcapsules and phase changematerial, manufactured by Microtek Laboratories, Inc.).

Water was flashed off as the microcapsules containing the phase changematerial was added to and dispersed in the molten homopolymer. Mixingcontinued until less than about 0.15 percent by weight of the waterremained (as measured using Karl-Fischer titration). The resulting firstblend was then cooled and chopped to form a chopped material for furtherprocessing.

A dry blend was then formed by dry blending about thirty pounds of thechopped material with about seventy pounds of a fiber-gradepolypropylene thermoplastic polymer (Polypropylene homopolymer 6852,manufactured by BP Amoco Polymers).

The resulting dry blend was then extruded using a 2½ inch single screwextruder with all zones set at about 230° C., with a screw speed ofabout 70 rpm, with 150 mesh filter screens, and with a nitrogen purge.In this manner, pellets were formed. The pellets were then driedovernight in a desiccant bed polymer pellet drying system at 105° C. andat −40° C. dewpoint. These pellets provided 23.1 J/g of thermal energystorage capacity (i.e., latent heat) as measured by DSC (DifferentialScanning Calorimeter) measurements.

Multi-component fibers (here, bi-component fibers) were then melt spunusing a bi-component fiber spin pack at temperatures between 230° and245° C. Spin packs of this general type are described in Hills, U.S.Pat. No. 5,162,074, entitled “Method of Making Plural Component Fibers”.The pellets were used to from core members, and polypropylene or nylonwas used to form sheath members.

Multi-component fibers formed with various core/sheath ratios andpolymeric materials were produced. With reference to FIG. 6, a number ofproperties and manufacturing parameters of six core/sheath fibers thatwere produced are set forth. These fibers all incorporate a phase changematerial and microcapsules that contain the phase change material(“mPCM”), which makes up about 15 percent by weight of each fiber's coremember and from about 7.5 percent to about 11.25 percent by weight ofeach fiber's total weight. Samples 1, 2 and 3 have a sheath membercomprising polypropylene (“PP”), which is a polypropylene homopolymerfrom BP Amoco Polymers. Samples 4, 5 and 6 have a sheath membercomprising Nylon 6, which is produced under the name Ultramid B fromBASF Corp.

Example 2

Various polyethylene-co-vinyl acetate (“EVA”) pellets were imbibed withK19 paraffin wax (melt point 29° C., 150 J/g latent heat, manufacturedby American Refining Group, Bradford, Pa.) by soaking and heating toswell the pellets. In particular, Elvax 350 (19 melt index, 25 percentby weight of vinyl acetate, manufactured by DuPont Inc.) and Elvax 450(8 melt index, 18 percent by weight of vinyl acetate, manufactured byDuPont Inc.) pellets were heated for various times and temperatures. Thepellets were filtered away from the remainder of the paraffin wax in adrain tank, and the amount of paraffin wax imbibed into the pellets wascalculated from initial and final pellet weights (i.e., as percentweight increase relative to initial pellet weights). Table 3 sets forththe results obtained under various conditions. TABLE 3 Imbibe EVA ImbibeTemp. % wax Type Time (hr) (° C.) imbibed Comments Elvax 1.0 50 16Sticky in drain tank. Drained more the next day. 450 Elvax 1.0 40 16Sticky in drain tank. Drained more the next day. 450 Elvax 1.0 80 Melted450 Elvax 1.0 55 16 Sticky in drain tank. Drained more the next day. 450Elvax 3.0 55 32 Sticky in drain tank. Drained more the next day. 450Elvax 2.0 55 26 Sticky in drain tank. Drained more the next day. 450Elvax 1.0 60 43 Sticky in drain tank. Drained more the next day. 450Elvax 2.0 60 43 Sticky in drain tank. Drained more the next day. 450Elvax 5.0 60 44 Sticky in drain tank. Drained more the next day. 450Elvax 3.0 60 39 Sticky in drain tank. Drained more the next day. 450Elvax 2.0 40 31 Dry in the drain tank. Stayed dry. Stuck lightly 350Elvax 3.5 40 38 Dry in the drain tank. Stayed dry. Stuck lightly 350Elvax 2.5 45 48 Dry in the drain tank. Stayed dry. Stuck lightly 350Elvax 2.0 40 20 Dry in the drain tank. Stayed dry. Stuck lightly 350Elvax 2.0 40 20 Dry in the drain tank. Stayed dry. Stuck lightly 350

Core/sheath fibers were then produced with a standard Hills, Inc.bi-component fiber spin pack using some of the pellets described aboveto form core members. In particular, core members were formed usingeither 26 percent wax imbibed Elvax 450 pellets or 31 percent waximbibed Elvax 350 pellets. Sheath members were formed using eitherpolyethylene terephthalate (Eastman F61HC, manufactured by EastmanChemical, Inc., Kingsport, Tenn.) (“PET”) or polytrimethyleneterephthalate (Corterra 509210, manufactured by Shell Chemical Corp.,Houston, Tex.) (“PTT”).

DSC measurements of the core/sheath fibers were made using a PerkinElmer Pyris 1 instrument. Cooling was accomplished using a FTS SystemsIntercooler 1, and data analysis was performed using a Perkin ElmerPyris Thermal Analysis System and Software for Windows, version 3.72.Test samples were prepared in Perkin Elmer hermetically sealed aluminumsample pans, and testing was performed while the test samples werecontinuously subjected to N₂ flow.

Test conditions comprised: 1) cooling the test samples to about −10° C.;2) isothermal hold for about 1 minute at −10° C.; 3) heating from −10°C. to about 50° C. at a rate of about 5° C. per minute; 4) isothermalhold for about 1 minute at 50° C.; and then 5) cooling from 50° C. toabout −10° C. at a rate of about 5° C. per minute. Results werecalculated using automatic machine integration of the measuredcrystallization exotherm peak of the paraffin wax. Table 4 sets forthvarious properties of the core/sheath fibers. TABLE 4 Sheath Core LatentHeat Denier/ Tenacity Elongation Member Member (J/g) filament (g/d) (%)PTT 26% wax 12.3 4.4 2.2 35 imbibed Elvax 450 PET 31% wax 6.9 3.7 2.8 30imbibed Elvax 350 PET 31% wax 8.4 34.5 1.43 57 imbibed Elvax 350

Each of the patent applications, patents, publications, and otherpublished documents mentioned or referred to in this specification isherein incorporated by reference in its entirety, to the same extent asif each individual patent application, patent, publication, and otherpublished document was specifically and individually indicated to beincorporated by reference.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention as defined by the appended claims. In addition, manymodifications may be made to adapt a particular situation, material,composition of matter, method, process step or steps, to the objective,spirit and scope of the present invention. All such modifications areintended to be within the scope of the claims appended hereto. Inparticular, while the methods disclosed herein have been described withreference to particular steps performed in a particular order, it willbe understood that these steps may be combined, sub-divided, orre-ordered to form an equivalent method without departing from theteachings of the present invention. Accordingly, unless specificallyindicated herein, the order and grouping of the steps is not alimitation of the present invention.

1-92. (canceled)
 93. A fabric comprising a plurality of fibers blendedtogether, wherein at least one fiber exhibits enhanced reversiblethermal properties and comprises: at least one inner member comprising ablend of a first polymeric material and a temperature regulatingmaterial, wherein the inner member extends through substantially thelength of the fiber; and an outer member forming the exterior of thefiber and surrounding the inner member, wherein the outer membercomprises a second polymeric material.
 94. The fabric of claim 93,wherein the inner member comprises at least two different temperatureregulating materials.
 95. The fabric of claim 93, wherein the fabriccomprises a plurality of fibers exhibiting enhanced reversible thermalproperties, and wherein at least two fibers comprise differenttemperature regulating materials.
 96. The fabric of claim 93, whereinthe fiber comprises a plurality of inner members surrounded by the outermember.
 97. The fabric of claim 96, wherein at least two of the innermembers comprise different temperature regulating materials.
 98. Thefabric of claim 93, wherein the plurality of fibers are blended togetherby a woven process or a non-woven process.
 99. The fabric of claim 93,wherein the plurality of fibers are blended together by a spunbondprocess.
 100. A fabric comprising a plurality of fibers blendedtogether, wherein at least one fiber exhibits enhanced reversiblethermal properties and comprises: a fiber body formed from a pluralityof elongated members, at least one of the elongated members comprising atemperature regulating material dispersed therein.
 101. The fabric ofclaim 100, wherein the temperature regulating material comprises a phasechange material.
 102. The fabric of claim 101, wherein the phase changematerial is selected from the group consisting of hydrocarbons, hydratedsalts, waxes, oils, water, fatty acids, fatty acid esters, dibasicacids, dibasic esters, 1-halides, primary alcohols, aromatic compounds,clathrates, semi-clathrates, gas clathrates, stearic anhydride, ethylenecarbonate, polyhydric alcohols, polymers, metals, and mixtures thereof.103. The fabric of claim 101, wherein the temperature regulatingmaterial further comprises a plurality of microcapsules that contain thephase change material.
 104. The fabric of claim 101, wherein thetemperature regulating material further comprises silica particles,zeolite particles, carbon particles, or an absorbent materialimpregnated with the phase change material.
 105. The fabric of claim100, wherein the elongated members are arranged in an island-in-seaconfiguration, a segmented-pie configuration, a core-sheathconfiguration, a side-by-side configuration, or a striped configuration.106. The fabric of claim 100, wherein a cross sectional shape of thefiber body is circular, multi-lobal, octagonal, oval, pentagonal,rectangular, square-shaped, trapezoidal, or triangular.
 107. The fabricof claim 100, wherein the fiber body is between 0.1 and 1000 denier.108. The fabric of claim 100, further comprising an additive dispersedwithin at least one of the elongated members, wherein the additive isselected from the group consisting of water, surfactants, dispersants,anti-foam agents, antioxidants, thermal stabilizers, light stabilizers,UV stabilizers, microwave absorbing additives, reinforcing fibers,conductive fibers, conductive particles, lubricants, process aids, fireretardants, anti-blocking additives, anti-fogging additives, anti-staticadditives, anti-microbials, crosslinkers, controlled degradation agents,colorants, pigments, dyes, fluorescent whitening agents, opticalbrighteners, fillers, coupling agents, reinforcement agents,crystallization agents, nucleation agents, and mixtures thereof. 109.The fabric of claim 100, wherein the plurality of fibers are blendedtogether by a woven process, a non-woven process, or a knitted process.